In a flat panel display such as a liquid crystal display or an organic EL (Electro-Luminescence) display, an active matrix thin film transistor (TFT) has been widely used for a drive transistor that drives a panel. Each pixel is provided with such a TFT to make it possible to control brightness and darkness of each pixel, attaining higher image quality and higher contrast compared to a passive matrix method.
Moreover, in such a flat panel display, further improvement in performance is being pursued. For example, there has been proposed a technique in which a gate insulating film of a TFT and a dielectric film of a capacitor are fabricated in different layers to allow selection of an optimum dielectric film without restrictions by TFT materials (For example, see Patent Literature 1). Such a dielectric film allows, for example, selection of a material having a higher dielectric constant than that of the gate insulating film, or allows smaller thickness for the same material as the gate insulating film, leading to enhanced capacity per unit area.